Defence Scheme No. 1 was created on April 12 of 1921 and details a surprise counterattack on the northern U.S. as soon as possible after evidence was received of an American invasion of Canada.
According to the plan,
Canadian troops stationed in
Pacific Command in Western Canada would immediately be sent to seize
Seattle, Washington; Canadian Forces stationed in
Prairie Command in Western Canada would be sent to attack
Great Falls, Montana and then move to
Minneapolis, Minnesota; and Canadian Forces stationed in
Quebec Command would be sent to seize
Albany, New York in a surprise counterattack while Canadian Forces in
Maritime Command would counterattack into
Maine.
[1] Meanwhile, according to the plan (See 1st item under 'External Links' below), the Canadian Forces
Great Lakes Command in Ontario was assumed to be fighting on the defensive against the main attack from the Armed Forces of the USA; if Canadian forces were successful in defending in the Great Lakes area, they were encouraged to launch counterattacks in the area of the
Niagara River and the
St. Clair River.
When resistance stiffened, the Canadians would retreat to their own borders, destroying
bridges and
railways to hinder American pursuit.
[1] The purpose of the invasion would be to allow time for Canada to prepare its war effort and to receive aid from
Britain, or to limit the American invasion before the US government opted to discontinue the incursions. Defence Scheme No. 1 serves as a counterpart to the American
War Plan Red, a plan to invade Canada drafted in 1930.
I fond it on Wikipedia for those who are curious.